KYIV -- Hundreds of demonstrators, including Ukrainian lawmakers, paraded through Kyiv on March 8 to demand the immediate release by Russia of the captured Ukrainian military pilot Nadia Savchenko.

More than 500 demonstrators marched from Ukraine's Defense Ministry to the Russian Embassy, where they handed over a petition addressed to Russian President Vladimir Putin urging him to set Savchenko free.

U.S. Secretary of State John Kerry on March 8 also called for her release, expressing concern about her health and welfare.

In a statement, Kerry said Savchenko during the past 20 months "has reportedly endured interrogations, solitary confinement, and forced 'psychiatric evaluation.' Her trial and continuing imprisonment demonstrate disregard for international standards, as well as for Russia's commitments under the Minsk agreements."

Savchenko has refused food and water since March 3 to protest her continued detention.

A Russian military court refused to allow Savchenko to make a final statement when closing arguments were presented by her lawyers on March 3.

The court called, instead, for her trial to be adjourned for a week before she has another chance to speak to the court.

Nadia Savchenko (file photo)

Ukrainian lawmaker from President Petro Poroshenko's party said a team of doctors was leaving Kyiv on March 8 for the southern Russian detention center where Savchenko is being held.

"Ukrainian diplomats have been able to wrest an agreement from the Russian authorities to allow our doctors to see [Savchenko] on March 9," Iryna Herashchenko wrote on Facebook.

Russian prosecutors have accused Savchenko of being a spotter who called in coordinates for a mortar attack that killed the two Russian journalists in eastern Ukraine shortly before she was captured there in June 2014.

Her defense lawyers argued that her mobile phone records prove she had been captured by Russia-backed separatists before the mortar attack.

Savchenko denies any role in the deaths of the journalists and says she was taken into Russia illegally by separatists after she was captured.

Ukraine's government says she has been subjected to a political show trial and that she should be treated as a prisoner of war rather than a criminal.